Germany’s Lanxess (LXSG.DE) is selling its 50 percent stake in synthetic-rubber maker Arlanxeo to partner Saudi Aramco IPO-ARMO.SE for around 1.4 billion euros ($1.6 billion) in cash in a deal it said will give it more flexibility to grow.

The deal marks an early exit for Lanxess from the world’s largest provider of synthetic rubber for tyres, while the Saudi state oil giant said it would “accelerate the development of growth opportunities in the kingdom, leveraging the strong feedstock position of Saudi Aramco”.

Aramco, which is planning to go public and looking to buy a stake in petrochemicals maker SABIC 2010.SE, plays a key role in Crown Prince Mohammed bin Salman’s ambitions to diversify Saudi Arabia’s economy beyond oil.

“The proposed purchase underscores Saudi Aramco’s strategy to further diversify our downstream portfolio and strengthen our capabilities across the entire petroleum and chemicals value chain,” Aramco’s Senior Vice President of Downstream, Abdulaziz al-Judaimi said in a statement on Wednesday.

For Lanxess chief executive Matthias Zachert the sale will allow him to focus on more deals to strengthen its specialty chemicals activities. Lanxess has previously said it would keep the remaining half of Arlanxeo until at least 2021.

The German chemicals group expects to receive about 1.4 billion euros in cash from the deal, which is expected to complete by end of 2018, valuing all of Arlanxeo at 3.0 billion euros including debt and liabilities.

Aramco plans to boost investments in refining and petrochemicals to secure new markets and sees growth in chemicals as central to cut the risk of an oil demand slowdown.

The sale in 2015 of the first 50 percent of Arlanxeo to Saudi Aramco had valued the business at 2.75 billion euros, and was pushed by Zachert at the time to make the company less volatile amid signs of increasing global rubber oversupply.

“We increase the resilience of our business, strengthen our financial basis and gain additional strategic flexibility for further growth,” Zachert said in a statement.

Zachert has pursued deals to grow in smaller but more profitable specialty markets and vowed last year he would change the company further.

Sources familiar with the company have said the CEO could consider another takeover the size of Chemtura. Lanxess bought the U.S. maker of additives for lubricants and flame retardants for 2.4 billion euros including debt last year.